This invention relates to phased antenna arrays and more particularly to a jammer signal rejection arrangement for such arrays.
Jammer rejection arrangements for phased antenna arrays as described in the technical literature control the phase and amplitude of the received signal from each element of the phased antenna array in an attempt to create a pattern null in the direction of each existing jammer signal source.
Another approach was described by S. P. Applebaum, Syracuse University Research Corporation, in which an antenna beam is pointed at the jammer signal source, in addition to an antenna beam being pointed at the desired signal source, and correlation between the signal outputs resulting from these two beams is used to neutralize the jammer signal in the desired signal.
The disadvantages of the null generating arrangement are that it is horribly complex for practical array sizes, it requires the use of a fast digital computer with large memory, independent means must be used to distinguish the desired signal from the jammer signals, and for several jammer sources, overall stability is dependent upon a large number of variable factors which are difficult to define in a practical situation.
The Applebaum arrangement is limited in performance, even with a single jammer, because of the Presence of the desired signal in the beam pointed at the jammer signal source. There is no information on how the Applebaum arrangement handles the multiple jammer situation.